Thin shell cementitious coated shear wall structural panel assembly and method of manufacture

ABSTRACT

This invention relates to an improved shear wall structural panel assembly that is able to resist gravity loads and lateral forces imposed by wind and earthquake loads. The panel comprises a substantially rectangular frame assembly that is constructed from a plurality of vertical frame members dispensed between and perpendicular to two horizontal frame members. There is a water barrier that is approximately the size of the frame assembly that is fixedly attached to and covering one side of the frame assembly. A reinforcement layer covers and is attached to the water barrier. Four outer frame members are fixedly attached to the perimeter of the frame assembly holding the aforementioned water barrier and reinforcement layer securely in place. A cementitious layer is adjacent to, covering and bonded to said reinforcement layer.

CROSS-REFERENCE TO RELATED APPLICATIONS:

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application Ser. No. 60/932,283 entitled “Thin ShellCementitious Coated Shear Wall Structural Panel, Method of Fabricationand Assembly to Create a Structure” filed on May 29, 2007, by thepresent inventor, Michael C. Lewis, the entire disclosure of which isherein incorporated by reference for all purposes.

BACKGROUND OF THE INVENTION Field of the Invention

This invention generally relates to structural panel assemblies that areused in residential and other types of building construction. Inparticular, to improved panel assemblies which are able to resistgravity loads and lateral forces imposed by wind and earthquake loads.

GENERAL BACKGROUND

Interior residential and light commercial wall, roofing, and flooringsystems commonly include plywood or oriented strand board (OSB) nailedto a wooden frame or mechanically fastened to a metal frame. OSBconsists of pieces of wood glued together and formed into a sheetsimilar to a sheet of plywood. Other applications use all or a partialsteel frame structure.

Regardless of whether the frame of a building is constructed from woodand/or steel, such frame structures are commonly subjected to a varietyof forces. Among the most significant of such forces are gravity, wind,and seismic forces. Gravity is a vertically acting force while wind andseismic forces are primarily laterally acting.

One of the primary functions of a shear wall is to dissipate energy fromseismic or wind loads while sustaining minimal damage to the shear wallstructure. Not all sheathing panels are capable of resisting suchforces, nor are they very resilient. Some will fail particularly atpoints where the panel is fastened to the framing. Where it is necessaryto demonstrate shear resistance, the sheathing panels are tested todetermine the load which the panel can resist within an alloweddeflection without failure.

The walls of a structure fabricated from wood components are commonlyformed from a collection of wall studs that are connected to top andbottom members or “plates” at desired spacing schemes (i.e., 16 inchesfrom stud center to center). The studs and plates usually comprisenominal 2 inch by 4 inch and/or 2 inch by 6 inch boards. In metal framearrangements, the studs and plates commonly comprise C-shaped membersthat are interconnected, for example, by screws or other fasteningtechniques.

To provide the frame with resistance to the types of lateral forcesmentioned above, shear wall panels are commonly attached to portions ofthe frame forms by the vertically extending studs and top and bottomplates such that they extend there between. For example, in a wood frameconstruction, a shear wall panel is commonly formed by the applicationof one or more types of sheathing such as plywood or oriented strandboard (OSB) to the outside or both sides of the wall frame. Thesheathing may be fastened to the wall frame at many points, thuscreating a shear wall panel. The shear wall panel is used to transferthe lateral forces acting on the frame of the building to the walls ofsubsequent floors below it and ultimately to the foundation upon whichthe walls are supported.

Sheathing panels used where a shear rating must be met usually areplywood or OSB. These panels can provide the needed shear strength.Unfortunately, both plywood and OSB are combustible and neither plywoodnor OSB is durable when exposed to water. Water intrusion between thepanels affixed on either side of the wall flame (hereinafter, the“building envelope”) accounts for the majority of structural defectclaims. For example, water intrusion causes deterioration of thestructural wood elements (studs and sheathing) within the wall due tosoft-rot and decay fungi. Water intrusion also allows mold growth whichcan be a human health hazard.

Shear rating is a common building industry structural test that followsthe guidelines set out in ASTM E72, ASTM E564, and ASTM E2126. Shearrating is based on the testing of two or three identical eight by eightfoot assemblies, i.e., panels fastened to framing. One edge is fixed inplace while a lateral force is applied to a free end of the assemblyuntil the load is no longer carried and the assembly fails. The measuredshear strength will vary, depending upon the thickness of the panel andthe size and spacing of the nails or mechanical fasteners used in theassembly. As the thickness of the panel affects its physical andmechanical properties, e.g., weight, load carrying capacity, rackingstrength and the like, the desired properties also vary according to thethickness of the panel. The measured strength will vary as the nail ormechanical fastener size and spacing is changed, as the ASTM E72, ASTME564, and ASTM E2126 tests provide. This ultimate strength will bereduced by a safety factor, e.g., typically a factor of two to three, toset the design shear strength for the panel.

In recent years, building construction techniques have experienced arapid transition from traditional “stick” building to less laborintensive methods. Among these newer developments, “panelization” hasemerged as one of the more promising building construction methods. Thissuccess is due primarily to two attributes of panelized buildingsystems: 1) opportunity for extensive customization; and 2)substantially reduced construction time as evidenced by erection of aweather tight shell in a week or less. Residential and commercialcustomers alike continue to find this combination extremely desirable.

Panelized construction provides a way to greatly expedite on-siteconstruction for a building module and may also be particularlybeneficial for increasing the speed and efficiency with which a housingaddition can be built. Panelized construction allows a considerableamount of the construction to be done in a factory off-site. Off-siteconstruction benefits from mass production, resident expertise, andsuperior quality control. Panelized construction allows a buildingmodule design to be broken down into manageable portions, such as fourfoot, eight foot, twelve foot, or sixteen foot wide walls, roofs, andfloor sections. Because the panels may be substantially flat and offairly standardized size, it is practical to move large numbers of themover great distances using conventional hauling methods.

Panelized construction also facilitates interchangeability andcustomization of building module designs. By using standardized wall,ceiling, and floor panels, building module designs may be easilyredesigned and customized. Exterior walls may be shifted andinterchanged to provide a near infinite variety of designs based on arelatively small selection of panels. Variety of design andcustomization may be particularly beneficial to housing additions.Different homeowners may have radically varying needs. Some may needadditional bedroom space, while others may need additional garage space,a home office, family room, playroom, or utility room.

The efficiency of construction of the housing addition may be furtherenhanced by providing as much of the construction as is feasible to bepre-installed in the panel. A panel may include a frame which providesthe structure of the building module. Additionally, pre-installation ofdoors, windows, and skylights within the panel frames may substantiallydecrease on-site building time. Pre-installing insulation and bothinterior and exterior wall covering layers on the frame may alsosubstantially decrease on-site building time. For example, a sheetingand siding on the exterior surfaces. Another way to improve on-sitebuilding times is to provide one or more house systems at leastpartially built into the pre-fabricated panels. For example, thepre-fabricated panels may be provided with electrical wiring, outletboxes, and electrically fixture housings, such as lighting and fanfixture housings, pre-installed. Panels may also be pre-installed withother wiring networks, such as cable telephone, audio wiring, securitysystems, and others. Panels may also be pre-installed with portions of aplumbing, heating, ventilation, or air conditioning systems.

Another way to increase the speed with which a panelized building modulemay be completed is to provide pre-fabricated panels and building moduledesigns which meet or exceed the residential building codes ofjurisdictions in which the building modules may be constructed. Whilethis may not directly increase the actual speed with which the buildingmodule is assembled, it may radically decrease the time required tosecure permits and inspections. Further, it may prevent costly delays,rebuilds and modifications due to failed inspections. Standardizedbuilding codes are frequently adopted with little or no modification ina plurality of jurisdictions. Standardized building codes may facilitatethe ability to produce panels and building module designs complying withthe building codes in a plurality of jurisdictions. Standardizedbuilding codes may include: the Standard Building Code, the BOCANational Building Code, the Uniform Building Code, the Canadian BuildingCode, the International Building Code, International Residential Codeand other such building codes.

A common problem encountered with the pre-fabricated wall systems (suchas structurally insulated panels (SIPs)) proposed by the prior art isthe difficulty in providing access therein for workmen to installin-wall and through-wall services.

Further difficulty is experienced when considering combinations ofdifferent materials such as concrete wall panels with brick and/or brickfacing. Such combinations of different construction materials havegained in popularity, where a section of the building being constructedincluded concrete exterior walls and, in addition, brick faced sections.Providing pre-fabricated building walls which are combination brickfacings and concrete panels is esthetically attractive but difficult andexpensive to produce. Means to provide such combinations have not as yetbeen provided except by the used of embossing a brick pattern upon aconcrete surface. The resultant product is far from the estheticappearance obtained when actual brick is employed.

Prior Art

Of the plurality of pre-fabricated building walls provided by the priorart, several of the most pertinent patent applications and issuedpatents with regard to the present invention are discussed below.

U.S. Pat. Application No. 2007/0175126 filed by Tonyan and Reicherts onDec. 7, 2006, describes a cementitious shear panel that may bemechanically or adhesively attached to a load bearing frame.Unfortunately, mechanical attachments such as screws or nails createholes in the panel where moisture may intrude. The Tonyan and Reichertspanel also requires cutting of the panels to size, thereby creatingwaste. Furthermore, adhesive attachment of structural shear panels isnot recognized by building codes. FIG. 34 of Tonyan and Reicherts showsASTM E72 racking test results indicating a low strength system withextremely low ductility. This makes the system undesirable for shearwall use and severely limits the usefulness of the invention.

U.S. Pat. No. 3,693,304 issued to Shell on Jul. 29, 1970, discloses abuilding panel and wall that uses a heavy gauge steel frame and a thicklayer of concrete. This configuration is rarely used for residential orother types of light construction. Shell also leaves a large portion ofthe steel frame exposed to weathering and subject to oxidation andcorrosion. The Shell panels would be much too heavy and expensive tocompete with traditional construction currently used for residential orother types of light construction.

U.S. Pat. No. 3,760,540 issued to Latoria et al. on Sep. 8, 1971,describes pre-cast concrete building panels consisting of a steelloading bearing frame with a thick layer of concrete with steelreinforcement within the concrete layer. Use of steel reinforcementgenerally requires at least one inch of concrete cover over each side ofthe steel reinforcement to protect it from corrosion. Therefore, the useof steel reinforcement does not lend itself to a thin shell of concretenecessary to minimize weight, cost, and ease of assembly. Moreover,Latoria leaves a large portion of the steel frame exposed and subject tooxidation and corrosion. Similar to Shell, the Latoria panels would bemuch too heavy and expensive to complete with traditional constructioncurrently used for residential or other types of light construction.

U.S. Pat. No. 4,602,467 issued to Schilger on Jul. 2, 1984, discloses athin shell concrete wall panel with steel mesh reinforcement. Again, theuse of steel reinforcement generally requires at least one inch ofconcrete cover over each side of the steel reinforcement to protect itfrom corrosion. In fact, Schilger specifically points out that theconcrete shell needs to have thickness of at least 1.5 to 2 inches. Theconcrete disclosed in the Schilger patent is ordinary concrete that willlikely experience sizeable damage during a seismic even due to crackingand spalling of the concrete shell.

U.S. Pat. No. 6,837,013 issued to Foderberg et al. on Oct. 8, 2002,discloses another lightweight precast concrete wall system panel withsteel mesh reinforcement. As previously mentioned, the use of steelreinforcement generally requires at least one inch of concrete coverover each side of the steel reinforcement to protect it from corrosion.Similar to Schilger, Foderberg also discloses a thickness preference of1.5 to 2 inch for their concrete shell. Furthermore, Foderberg disclosesa panel that is separate from the load bearing wall and is attached tothe load bearing wall by lifting the panel with heavy equipment andattaching it to the load bearing wall with screws. In addition to thelikely damage due to cracking and spalling of the described ordinaryconcrete during a seismic event, the Foderberg wall system panels wouldbe very labor intensive to produce and install, thereby making this wallsystem cost prohibitive for residential or other light constructionprojects.

U.S. Pat. No. 7,278,244 issued to Rubio on May 27, 2005, discloses aconcrete stud wall system with steel mesh reinforcement. Rubio disclosesat least 1.5 to 2 inches of concrete cover over each side of the steelreinforcement to protect it from corrosion. Rubio would likelyexperience much more damage during a seismic event than the presentinvention due to cracking and spalling of the ordinary concrete shell.

There is a need for a versatile pre-fabricated wall system that isrelatively low cost for facile insallation and production; light weightyet structurally strong enough to be used as basement walls,foundations, floors and roofs; easily combined and assembled to otherdesirable finish materials, such as brick or stone, to enhance theaesthetics of the wall system; offers excellent thermal-resistive andweather-resistive characteristics; and, is capable of multi-levelincorporation in a building structure.

OBJECTS AND ADVANTAGES OF THE PRESENT INVENTION

It is one object of the shear wall structural panel component of thepresent invention to replace the plywood or oriented strand board (OSB)and the siding with one shear wall panel component that is thestructural shear panel and the exterior siding. This will reduce thenumber of assembly components thereby reducing construction time andcost.

Another object of the present invention is to make panels larger thanthe prior art shear walls thereby speeding construction and reducing thenumber of seams that occur between pieces of exterior siding. Minimizingthe seams minimizes potential moisture penetration and subsequentmoisture damage.

Another object of the present invention is to use a high performanceductile concrete for the outer shell and a non-metallic, thinnerreinforcement layer thereby allowing the required thickness of the outercementitious shell to be considerably thinner than the prior art socalled ‘thin shell’ panels. By combining a wood flame with a true thinshell, the structure dead load is reduced allowing for a relativelylight and open structure.

It is another object of the present invention is to provide a shear wallthat has improved shear load capacity and stiffness.

It is yet another object of the present invention to provide a shearwall exhibiting improved energy absorption and ductility that willexperience much less damage under loading compared to other shear wallsystems.

Another object of the present invention is to provide a shear wallstructural panel that may be used an alternative to costly masonryconstruction.

It is yet another object of the present invention to provide a shearwall that has a vastly superior building envelope that is unaffected bymoisture intrusion and provides a means of escape to water that doesintrude; is resistant to mold and decay fungi, thus reducing structuraldefect claims; is resistant to insect attack by termites and carpenterants and intrusion of pests such as mice; is fire resistant; and is muchmore durable than wood or normal concrete, all of which ultimatelyreduces maintenance costs.

SUMMARY OF THE INVENTION

The present invention is an improved shear wall structural panelassembly that resists gravity loads and lateral forces imposed by windand earthquake loads. The shear wall structural panel comprises asubstantially rectangular frame assembly that is constructed from aplurality of vertical frame members dispensed between and perpendicularto two horizontal frame members. A water barrier that is approximatelythe size of the frame assembly is fixedly attached to and covering oneside of the frame assembly. A reinforcement layer covers and is attachedto the water barrier. Four outer frame members are fixedly attached tothe perimeter of the frame assembly holding the aforementioned waterbarrier and reinforcement layer securely in place. A cementitious layeris adjacent to, covering and bonded to the reinforcement layer.

The shear wall structural panel assembly of the present invention is acombined load bearing and shear wall that also provides exterior siding.

BRIEF DESCRIPTION OF THE DRAWINGS

The above description and other objects, advantages, and features of thepresent invention will be more fully understood and appreciated byreference to the specification and accompanying drawings, wherein:

FIG. 1 is an exploded view of a shear wall structural panel depictingthe primary layers of the panel wall of the present invention.

FIG. 2 is a front elevation view of the frame assembly of the presentinvention.

FIG. 3 is a cross-sectional view at line 3-3 of FIG. 2.

FIG. 4 is a perspective view of one embodiment of an assembled shearwall structural panel assembly of the present invention.

FIG. 5 is a sectional view of the lower left corner of the assembledshear wall panel of FIG. 4 detailing the layers and components of thepresent invention.

FIG. 6A is a cross-sectional side view at line 6-6 of FIG. 4.

FIG. 6B is an enlarged view of the FIG. 6A further detailing thecomponents of the assembly.

FIG. 7 is a front view of the lower right corner of the shear wallstructural panel assembly of the present invention illustrating theplacement of weep openings and flashing used in one embodiment of thepresent invention.

DRAWINGS REFERENCE NUMERALS

100 Initial Frame Assembly

120 Water Barrier

130 Thin Shell Cementitious Panel (TSCP)

140 Reinforcement Layer

200 Frame Assembly

202 Corner Brackets

204 Outer Frame Member

208 Vertical Frame Member

220 Horizontal Frame Member

400 Shear Wall Structural Panel Assembly

402 Fasteners

502 TSCP Step

602 Flashing

604 Flashing Attach Tab

606 Tab Fastener

610 Weep Opening

702 Initial Frame Fastener

DETAILED DISCUSSION OF THE EMBODIMENTS

Referring to the figures, like elements retain their indicatorsthroughout the several views.

FIG. 1 is an exploded view of a shear wall structural panel assemblydepicting the primary components of the shear wall structural panelassembly of the present invention. Initial Frame Assembly 100, in thisembodiment, comprises several nominal two inch by six inch by eight footwood studs. The studs are fastened to one another for strength andstability by nails, screws, or other fastening means (not shown) as iscommon in the building trade.

In this embodiment, Water Barrier 120 is placed over Initial FrameAssembly 100 and attached to the outer surfaces of Initial FrameAssembly 100 using staples (not shown). Water Barrier 120 in thisembodiment is plastic sheeting that is commonly used in the buildingtrade to prevent moisture from contacting the wood structure. Oneexample of which is Dupont's Tyvek™ which is a high-density polyethylene(HDPE), although there are other suitable products as well.

It has also been contemplated to use multiple layers of Water Barrier120 when needed for added moisture control.

Reinforcement Layer 140 is stretched over Initial Wall Frame Assembly100 on top of Water Barrier 120. Reinforcement Layer 140 is attached inseveral places along each of the stud components of Initial Wall Frame100 as well as around the perimeter by fastening means such as staples,nails or tacks (not shown). Reinforcement Layer 140 may be metal sheet,wire mesh, polymer grid, polymer fabric or other suitable material. Someexamples of available products for Reinforcement Layer 140 are MirafiBasXGrid 11 or Mirafi HP370. In some applications, Reinforcement Layer140 may be eliminated from the design where wall strength is sufficientwithout it.

In another embodiment, each Vertical Frame Member 208 has wooden lathattached along its full length. The wooden lath creates a friction jointthat holds the reinforcement securely to the frame and acts to make theTSCP 130 composite with Initial Frame Assembly 100.

The outer edges of Water Barrier 120 are lifted upward over the top ofReinforcement Layer 140 and Outer Frame Members 204 are attached aroundthe perimeter of Initial Frame Assembly 100 thereby further securingReinforcement Layer 104 and Water Barrier 120. Reinforcement Layer 104is now disposed between two layers of Water Barrier 120. Corner Brackets202 are now attached using fastening means (not shown) such as screws,nails or the like. Water Barrier 120 is now wrapped over the top anddown the perimeter of the now attached Outer Frame Members 204. WaterBarrier 120 is attached using fastening means (not shown) such asstaples, nails, tacks or the like.

Thin Shell Cementitious Panel 130 (hereinafter “TSCP 130”) is a layer ofconcrete that is cast against Reinforcement Layer 140. The term“cementitious” includes but is not limited to concretes and mixturesthereof, and other building compositions which rely on hydraulic duringmechanisms. Suitable cements, such as lime cement, Portland cement,refractory dement, slag cement, expanding cement, pozzolanic cement,mixtures of cements, etc. may be used according to needed size andassociated strength.

In one embodiment, Engineered Cementitious Composite 28 (hereinafter“ECC 28”) concrete is used for TSCP 130. ECC 28 is a unique cementitiousmaterial that exhibits strain hardening and steady state flat crackingbehavior in tension and flexure. Steady state flat cracking behavioroccurs when each crack that initiates in the concrete matrix maintains auniform and very small width along the entire length of the crack. Thisallows the fibers in the concrete to continue transferring load, ordissipating energy, across the crack. ECC 28 can be ductile toapproximately 2% or more tensile strain.

The main energy dissipation modes for the present invention arefundamentally different from prior art wood sheathed walls. The thinshell cementitious panel wall of the present invention dissipates energythrough tensile strain hardening of the ECC 28 and/or plasticdeformation of Reinforcement Layer 140. Prior art wood shear wallsgenerally dissipate energy through inelastic fastener deformation,friction of components and crushing of the wood. This leads to extensivedamage and high cost of repair in the prior art shear walls.

To create TSCP 130 as shown in FIG. 1, ECC 28 concrete or the like iscast into a mold in a thin layer that is placed horizontally on a levelsurface. With TSCP 130 in an unset or soft state, Initial Frame Assembly100 and Outer Fame Members 204 with Water Barrier 120 and ReinforcementLayer 140 attached thereto is placed on top of TSCP 130 withReinforcement Layer 140 facing downward and thereby protruding into TSCP130. TSCP 130 encapsulates most of Reinforcement Layer 140. The assemblyis held in the proper position relative to TSCP 130 by small fixtures atseveral locations (not shown). This type of ‘face down’ concrete wallcasting is well known to those skilled in the art. Further details ofthe assembly process are forthcoming in the latter figure discussions.

Additionally, it has been contemplated to cast TSCP 130 in a ‘face up’configuration with the concrete being poured onto the attachedReinforcement Layer 140. To accomplish pouring the concrete ontoReinforcement Layer 140, Outer Frame Members 204 would act as a screedfor setting the level of the concrete used for TSCP 130. Before TSCP 130is fully set, in this embodiment, Outer Frame Members 204 are coveredwith set or unset concrete creating a TSCP step similar to TSCP Step 502that will discussed in FIG. 5.

It has also been contemplated to eliminate Water Barrier 120 ifReinforcement Layer 140 and/or TSCP 130 provide an adequate water ormoisture barrier.

In another embodiment, it has been contemplated to spray the concreteused to create TSCP 130 onto a vertical wall that is already assembledinto the shell of a structure.

FIG. 2 is a front elevation view of Frame Assembly 200 of the presentinvention. As previously discussed in FIG. 1, Initial Frame Assembly100, comprises several nominal two inch by six inch by eight foot woodenstuds. The studs are fastened to one another for strength and stabilityby nails, screws, or other fastening means (not shown) as is common inthe building trade. The overall size of the shear wall structural panelof the present invention is determined by the size of Frame Assembly.FIG. 2 depicts Frame Assembly 200 as an eight foot square. However,depending upon the application, Frame Assembly 200 can easily be made invarious widths and heights. For example, four by eight feet, eight byeight feet (as shown), ten by eight feet, or twelve by eight feet.

Vertical Frame Members 208 are spaced substantially equidistance apartand extend between and fastened to Horizontal Frame Members 220. Asdiscussed in FIG. 1, Water Barrier 120 (not shown) and ReinforcementLayer 140 (not shown) are disposed atop Initial Frame Assembly 100 butare not shown for clarity of placement of Outer Frame Members 204 whichare attached slightly above Initial Frame Assembly 100. The placement ofOuter Frame Members 204 is discussed in detail with the cross-sectionalview shown in FIG. 3.

For added security and shear strength, Corner Brackets 202 are attachedprior to the final attachment of Water Barrier 120 to the perimeter ofOuter Frame Members 204. This provides some protection from moisture andthe environment to Corner Brackets 202 as well.

In this embodiment, Corner Brackets 202 are 18 gauge thick sheet metal,approximately twenty inches long by approximately three inches wide andbent into an essentially 90 degree angle. Corner Brackets 202 can be ofvarious sizes and materials according to strength needs and wall size.It has also been contemplated to eliminate Corner Brackets 202 inapplications where the wall strength is adequate without them.

FIG. 3 is a cross-sectional view of Frame Assembly 200 at line 3-3 ofFIG. 2 depicting the relative placement of Initial Frame Assembly 100with Outer Frame Members 204. As depicted in FIG. 3, Outer Frame Members204 are attached an offset distance ‘d’ above Initial Frame Assembly100. The distance ‘d’ is approximately the thickness of TSCP 130 whichin this embodiment is approximately one half inch thick. This offsetprovides additional strength to the assembly by allowing TSCP 130 totransfer loads to Outer Frame Members 204.

In this embodiment, the previously discussed mold for face down castingwould have a slight recess, approximately the depth of distance ‘d’,around the perimeter to accommodate Outer Frame Members 204 with acoating of TSCP 130 as well as creating a step in the TSCP 130 layer.TSCP Step 502 covers and protects Outer Frame Members 204 fromweathering. TSCP Step 502 also allows an approximately one-half inchthick concrete shell over the interior portion of the wall, rather thanone inch thick across the entire panel width. A thick shell wastesmaterial and is not needed structurally. TSCP Step 502 also provides anaesthetically pleasing border to TSCP 130.

It has also been contemplated to set decorative elements such as thinbrick panels into the exterior surface of TSCP 130. Further, theexterior surface of TSCP 130 may be textured, patterned, or sculpted tolook like natural stone, brick, or the like. Texturing or patterning canbe created by sculpting the surface of the mold used for forming TSCP130. Additionally, coloring pigment may be added during the mixing ofTSCP 130 to minimize or eliminate the need for painting.

FIG. 4 is a perspective view of one embodiment of an assembled shearwall structural panel of the present invention. As previously discussed,Corner Brackets 202 are affixed to the upper corners. Although in thisembodiment Corner Brackets 202 are shown affixed exterior to WaterBarrier 120, this is primarily for clarity of placement as CornerBrackets 202 are preferably affixed interior to Water Barrier 120 toprotect them from the environment. Fasteners 402 are shown along theperimeter of Shear Wall Structural Panel Assembly 400. In thisembodiment, Fasteners 402 are nails of a length that extend throughWater Barrier 120, through Outer Frame Members 204, throughReinforcement Layer 140 sandwiched between two layers of Water Barrier120, and into Initial Frame Assembly 100.

Reinforcement Layer 140 and TSCP 130 work together to create a verystiff, yet ductile, panel under lateral loading conditions. This isaccomplished by carefully selecting Reinforcement Layer 140 with tensilestrain characteristics that complement those of the TSCP 130 and usingoptimum pre-stress force in dispensing or laying out Reinforcement Layer140. The pre-stressed Reinforcement Layer 140 is also intended to reducethe initial slippage of the shear wall components at the onset ofloading. Reinforcement Layer 140 also holds the framing members togetherduring loading. Pore size of Reinforcement Layer 140 has a direct effecton the strength of the bond between TSCP 130 and Reinforcement Layer140.

During lateral loading of traditional wood frame walls, the interiorgypsum wallboard components are damaged. This damage is due to gypsumwallboard having a higher stiffness than the wood shear panels. Thehigher stiffness attracts the load and damages the wallboard. One of thebenefits of the Shear Wall Structural Panel Assembly of the presentinvention is that the cementitious layer, ECC 28 in one embodiment, hasa higher stiffness than gypsum wallboard. This allows the gypsum panelsto sustain comparatively less damage during lateral loading as the ECC28 panels will attract the load rather than the gypsum. This could be asignificant cost savings associated with protecting the interior gypsumwallboard.

Completed Shear Wall Structural Panel Assembly 400 is joined to othersimilar completed assemblies along with floor and roof diaphragms. Usingappropriate fasteners and sealants, the complete structural shell of abuilding is produced.

This fabrication method can be conducted in a controlled indoorenvironment, such as a factory. The completed panel assemblies would beshipped to the building site and set in place using a small crane orother suitable methods. It has also been contemplated to fabricate thepanel assemblies at the building site or at any other suitable location.

When used in residential, light, and other suitable types ofconstruction, the Shear Wall Structural Panel Assembly 400 of thepresent invention provides superior performance as a lateral forceresisting system.

FIG. 5 is a sectional view of the lower left corner of Shear WallStructural Panel Assembly 400 of FIG. 4. As shown, Water Barrier 120 islaid over the top and one side of Horizontal Frame Members 220 andoutermost Vertical Frame Members 208—both subcomponents of Initial FrameAssembly 100. Reinforcement Layer 140 is disposed over Water Barrier 120and attached to all Vertical Frame Members 208, Horizontal Frame Members220 as well as the perimeter of Initial Frame Assembly 100 withattachment means (not shown) such as staples, nails, tacks or the like.In this embodiment, Water Barrier 120 is then brought up, overReinforcement Layer 140 and Outer Frame Members 204 are attached to theoutermost Horizontal Frame Members 220 and outermost Vertical FrameMembers 208. The remaining Water Barrier 120 is wrapped over Outer FrameMembers 204 and fastened in place with small staples (not shown).Fasteners 402 (not shown) extend through and secure all other layers.

In the FIG. 5 embodiment, TSCP Step 502 is shown around the perimeter ofthe TSCP 130 layer. As discussed in FIG. 3, TSCP Step 502 will beapproximately a height similar to distance ‘d’ that is created by OuterFrame Members 204 being attached slightly higher than Initial FrameAssembly 100.

FIG. 6A is a cross-sectional side view of Shear Wall Structural PanelAssembly 400 at line 6-6 of FIG. 4 further detailing the interior orenvelope of the panel assembly. Since TSCP 130 is impervious to water,it is important to have a means of allowing moisture that may get intothe envelope due to interior or exterior moisture sources to escape fromthe panel envelope.

As shown in FIG. 6A, Flashing 602 extends between Vertical Frame Members208 and attaches to the inside of Vertical Frame Members 208 at FlashingAttach Tabs 604 with Tab Fasteners 606. Tab Fasteners 606 are smalltacks, nails, or staples that extend through Flashing Attach Tabs 604.Flashing 602 is angled toward TSCP 130 at the base of the panel envelopeto divert any moisture away from Initial Frame Assembly 100.

FIG. 6B is an enlarged view of FIG. 6A further detailing the componentsin the panel envelope of Shear Wall Structural Panel Assembly 400. WeepOpening 610 is shown in phantom extending through TSCP 130. Weep Opening610 allows any moisture that may get into the panel envelope of ShearWall Structural Panel Assembly 400 to escape to the outside.

FIG. 7 is a front view of the lower right corner of Shear WallStructural Panel Assembly 400 of the present invention. Weep Openings610 are shown at the base of the panel envelope. In this embodiment,Weep Openings 610 are approximately 0.125″ in diameter with one or twoWeep Openings 610 disposed between Vertical Frame Members 208 just abovethe lower Horizontal Frame Member 220 thereby allowing any moisture inthe panel envelope to be expelled.

Wherein the terms and expressions which have been employed in theforegoing specification are used therein as terms of description and notof limitation, there is no intention, in the use of such terms andexpressions, of excluding equivalents of the features shown anddescribed or portions thereof, it being recognized that the scope of theinvention is defined and limited only by the claims which follow.

1. A shear wall structural panel assembly for resisting gravity and shear loads, comprising: a substantially rectangular frame assembly having a plurality of parallel vertical frame members dispensed between and perpendicular to two horizontal frame members, said frame assembly having an outer perimeter, a first side and a second side opposite said first side; a water barrier approximate the size of said frame assembly fixedly attached to and covering said first side of said frame assembly; a reinforcement layer approximate the size of said frame assembly fixedly attached to said frame assembly and covering said water barrier; and an outer frame assembly fixedly attached to said outer perimeter of said frame assembly; and a cementitious layer disposed on, covering and bonding to said reinforcement layer; wherein, the shear wall structural panel assembly is a combined load bearing wall, shear wall, and exterior siding.
 2. The shear wall structural panel assembly of claim 1, wherein said vertical frame members and said horizontal frame members are nominal two inch by six inch wood studs.
 3. The shear wall structural panel assembly of claim 1, wherein said water barrier is breathable plastic sheeting.
 4. The shear wall structural panel assembly of claim 1, wherein said reinforcement layer is a polymer mesh.
 5. The shear wall structural panel assembly of claim 1, wherein said outer frame assembly is a plurality of nominal two inch by four inch wood studs.
 6. The shear wall structural panel assembly of claim 1, wherein said cementitious layer is concrete comprising, on a dry basis, 45 to 75 weight percent cementitious power, 10 to 30 weight percent sand, 1 to 5 weight percent polyvinyl alcohol fibers, and 0.5 to 2.0 weight percent chemical admixture, said continuous phase being reinforced with polyvinyl alcohol fibers.
 7. The shear wall structural panel assembly of claim 1, further comprising at least two corner reinforcement brackets fixedly attached to at least two exterior corners of said outer flame assembly.
 8. The shear wall structural panel assembly of claim 1, wherein each of said vertical flame members has a wood lath fixedly attached to and extending the length of said vertical flame members, wherein said wood lath secures said reinforcement layer to said frame assembly prior to application of said cementitious layer.
 9. The shear wall structural panel assembly of claim 1, wherein said cementitious layer is sprayed onto and bonded to said reinforcement layer with said the shear wall structural panel assembly vertically oriented.
 10. The shear wall structural panel assembly of claim 1, further comprising at least one weep opening extending through said cementitious layer, through said reinforcement layer and through said water barrier, wherein moisture inside the panel is allowed to escape.
 11. The shear wall structural panel assembly of claim 10, further comprising a portion of flashing spanning between and perpendicular to each of said vertical frame members, said flashing extends downward from said second side of said frame assembly to said first side of said frame assembly and below said weep openings.
 12. The shear wall structural panel assembly of claim 1, wherein said outer frame assembly is extended a distance above said first side of said frame assembly creating a frame step, said cementitious layer is dispensed on said reinforcement layer and said outer frame assembly creating a cementitious step having a height of said distance, wherein, said frame step provides added strength to the shear wall structural panel assembly.
 13. The shear wall structural panel assembly of claim 1, wherein said cementitious layer further comprises a colorant eliminating the need for exterior painting.
 14. The shear wall structural panel assembly of claim 1, wherein said cementitious layer 15 further comprises an exterior having aesthetic surface features.
 15. The shear wall structural panel assembly of claim 12, wherein said features are embedded stone veneer.
 16. The shear wall structural panel assembly of claim 12, wherein said features are embedded brick veneer.
 17. A method of manufacturing a shear wall structural panel assembly, comprising the steps of: providing a first frame structure having a plurality of parallel vertical frame members dispensed between and perpendicular to two horizontal frame members, said frame assembly having an outer perimeter, and a first side; attaching a water barrier approximate the size of said frame assembly covering said first side of said frame assembly; attaching a reinforcement layer approximate the size of said frame assembly to said frame assembly and covering said water barrier; attaching an outer frame assembly to said outer perimeter of said frame assembly creating a structural assembly having an assembly perimeter; providing a mold having an outer dimension approximate that of said assembly perimeter; dispensing a cementitious material to a depth in said mold; placing said structural assembly with said first side down onto said cementitious material in said mold, said cementitious layer bonding to said reinforcement layer; wherein, the shear wall structural panel assembly is a load bearing wall, shear wall, and exterior siding.
 18. The method of claim 17, wherein said outer frame assembly is extended a distance above said first side of said frame assembly creating a frame step, said cementitious layer is dispensed on said reinforcement layer and said outer frame assembly creating a cementitious step having a height of said distance, wherein, said frame step provides added strength to the shear wall structural panel assembly.
 19. The method of claim 17, further comprising the step of attaching at least two corner reinforcement brackets to at least two exterior corners of said outer frame assembly.
 20. The shear wall structural panel assembly of claim 1, wherein said outer frame assembly, said vertical frame members, and said horizontal frame member of said frame assembly and are light gauge steel. 